bog is a fennish area which can accumulate a lot of amount peat. It is a result of dead plant material which most of the time mosses. In general, this plant is a sphagnum moss. It is one of the four main types of wetlands. There is not only one name of it. Other names are mire, quagmire, muskeg; and alkaline mires are called fens. They are frequently covered in ericaceous shrubs strike root in the sphagnum moss and peat. The gradual accumulation of decayed plant material in a bog functions as a carbon sink.

Bogs appears there where the water at the ground surface is acidic and low in nutrients. In some cases, the water is derived entirely from precipitation. In this case they are termed ombrotrophic (rain-fed). Water flowing out of bogs has a characteristic brown color, which comes from dissolved peat tannins. In general, the low fertility and cool climate results in relatively slow plant growth, but decay is even slower owing to the saturated soil. Hence peat accumulates. Large areas of landscape can be covered many meters deep in peat.

The most ideal place for bogs which provide a cold temperature climate, commonly in boreal ecosystem. Bog can grow to a million kilometers. The biggest bog is situated on the western Siberia lowlands in Russia.